In the present scenario, it is easier than ever to disrupt Global Navigation Satellite System (GNSS) signals, thereby denying the systems that rely on accurate Positioning, Navigation and Timing (PNT) data. PNT is one of the most central elements of modern technology systems and devices, which we depend on an everyday basis. Nearly every critical system around the world banks on these signals and data. When it comes to military systems, failure isn’t an option. Leaders in the Department of Defence are concerned about over-reliance on this one form of technology. If GNSS guidance becomes unavailable, soldiers and drones in the battlefield could be rendered blind and unable to navigate. If that awareness is lost, even for a minute, the consequences can be disastrous. GNSS also plays an important role in the targeting and guidance systems in missiles. As such, GNSS has become both a strength and a vulnerability. The most important question now is: How can we protect essential systems from interference and denial-of-service attacks?
In the current scenario, electronic warfare has become a theatre of furious contention. The Indian Regional Navigation Satellite System (IRNSS), with the operational name NavIC, was developed partly because access to foreign government-controlled GNSS is not guaranteed in hostile situations, as was the case in 1999 when the US denied the Indian request for Global Positioning System (GPS) data in the Kargil region.
Electronic war has three basic elements: probe, attack and protect. Initially, intelligence is gathered by locating enemy electronic signals. On attack, ‘white noise’ jamming disables and degrades systems, including radio and cellphone communications, air defense and artillery radars. Then there is spoofing, which confuses and deceives. When it works, munitions miss their targets. Electronic signals emitted in battlefield can be used to track individuals and equipment.
The latest electronic warfare technology has the capability to disrupt communications, navigation and guidance systems and may also direct lethal blows. It may be used against artillery, fighter jets, cruise missiles, drones and many other equipment. Militaries may also use it to protect their forces. The same has also been observed in the Russia-Ukraine war, wherein the simple act of powering up a cellphone has been seen to draw a rain of deathly fire. Similarly, artillery radar and remote controls for unmanned aerial vehicles have invited showers of shrapnel.
In the early days of the war in Ukraine, drones were termed an astonishing source of success against Russian forces. Numerous stories and multiple video clips dominated the media, showing Ukraine’s drones demolishing the chaotic Russian advances. However, Russia learned from this humiliation in the first months of the invasion and soon established better organized and fielded electronic warfare and air defense systems.
A Ukrainian intelligence official called the Russian threat “pretty severe” when it came to disrupting reconnaissance efforts and commanders’ communications with troops. Russian jamming of GPS receivers on drones that Ukraine uses to locate the enemy and direct artillery fire is particularly intense “on the line of contact,” he said. Russia jammed GPS from Black Sea to Finland in the ongoing war. The European Aviation Safety Agency (EASA) said the issue was observed in the Russian enclave of Kaliningrad, the Baltics, Eastern Finland, the Black Sea, the Eastern Mediterranean and Northern Iraq.
Many important lessons may be learnt from the Russia-Ukraine war about multidomain warfare, particularly the proliferation of electronic attacks and countermeasures. While neither side has tapped, nor will hopefully, its most destructive electronic warfare resources in the future, both have employed jamming.
Communication jamming, as well as spoofing, are techniques intended to disrupt satellite communication. The US also accused Russia of interfering with their GPS signals in the ongoing war, which could be due to jamming or possibly spoofing. In early March 2022, Elon Musk-owned SpaceX noted that its Starlink signals that were providing satellite internet to Ukraine, had also been jammed.
In November 2021, Russia admitted to destroying one of its own satellites, implying a threat to target other satellites as well. If Russia were to target GPS satellites, it would cripple not just military capabilities but also much of the entire world’s logistical capabilities. It is therefore evident that there could be both large-scale (hard kill) and smaller-scale (jamming/spoofing) threats to the satellite-based navigation system.
Although GPS is an important component of the national PNT ecosystem, it is far from being the only source of capability for PNT. If GPS disruption makes it difficult to perform a task in an automated way, numerous manual strategies are available, even at the price of reduced efficiency, by using alternative niche technologies. Because of the importance of PNT in the modern economy, a wide range of technologies has been prepositioned, which could either supplement GNSS or provide it with backup.
The UK and the US are seeking alternatives to GPS that do not rely on satellites, among concerns that future wars could be fought by signal jammers without a single shot being fired. Many of these alternative and complementary PNT capabilities are already implemented broadly and some additional technologies are being implemented for public safety or other purposes.
No single system could be an ideal backup for GPS. Some systems, such as the European Union’s Galileo or Russia’s GLONASS are satellite systems very similar to GPS and could be a good substitute under certain circumstances (if GPS alone were spoofed or disrupted by a cyber-attack). However, under other circumstances, such as a solar storm, these similar satellite systems would also be unavailable, as they share the same vulnerabilities as GPS.
Terrestrial systems are divergent to GPS and have different weaknesses. But no single terrestrial system matches GPS on area coverage, on position accuracy, and likely on ubiquitous adoption of low-cost user equipment in the presence of continual, free GPS signals. Any single backup, therefore, will mitigate a GPS outage only for limited users. Modest investments by the government in threat detection could also reinforce private incentives to maintain a robust PNT ecosystem.
NavIC, our own RNSS, is equally vulnerable to space storms and can be disrupted to deny PNT signals. Both GPS and other GNSS constellations that broadcast on multiple frequencies and receivers, which take advantage of Dual Frequency Multi Constellation (DFMC) GNSS, are now becoming commonly available, including in smartphones, which can hop to a secondary constellation in case of disruption in the primary navigation system.
Long Range Navigation or LORAN-C was a timing and radio navigation service that used high-power signals from terrestrial antennas in the 90–110 kilohertz (kHz) band and was intended to provide positioning accurate to within about 460 meters. This level of accuracy was useful to mariners, although it was insufficient for harbor navigation. Still, since the error in repeatability of the position calculation and the relative location with respect to nearby users could be several times better, it was useful for the relative navigation and safety of ships. Enhanced LORAN or eLoran was designed to provide better positioning accuracy using the same transmitter sites and much of the existing Loran-C infrastructure. The eLoran system has been deployed in various countries, including Russia, China and South Korea.
NextNav LLC, USA has developed a system of terrestrial beacons known as the Metropolitan Beacon System (MBS), to provide precise PNT signals to mobile device users in covered areas. MBS consumes significantly less power than GNSS and includes high-precision altitude. NextNav’s Urban and Indoor Positioning service TerraPoiNT is available in the San Francisco Bay Area, in McLean, Virginia, and in other select markets. NextNav’s vertical location service, Pinnacle, is available in more than 4,400 cities nationwide, and the company has partnered with AT&T FirstNet to provide vertical location service for first responders.
Similarly, Locata Corporation, headquartered in Australia, has developed a system of terrestrial beacons to provide PNT signals to dedicated receivers in a localized area. The system can reportedly provide centimeter-level precision in positioning, with under one nanosecond timing synchronization between transmitters without the use of atomic clocks. Locata uses a proprietary signal in the same band as Wi-Fi transmitters and therefore performs similarly to Wi-Fi with respect to signal obstruction and interference. Locata has been awarded a multi-year sole-source contract with the 746th Test Squadron (746 TS) of the United States Air Force to deploy LocataNet and provide positioning information when GPS is jammed across a 2,500 square mile (6,475 sqaure kilometer) area off the White Sands Missile Range in New Mexico.
Pseudolites are terrestrial transmitters that broadcast signals compatible with existing GNSS user equipment on the same carrier frequency using a signal structure that is the same as any other GNSS. A key motivation for such systems is indoor PNT where Space-based signals are not available. Pseudolites can also have much higher signal strength than normal GNSS signals and thus offer greater resistance to jamming.
Although the standards for 5G cellular telephony are not fully established, some of its characteristics can be anticipated. Because of the nature of the technology associated with 5G, the expectation is that there will be a much higher density of transmitter nodes to connect with user devices. These nodes can very well be used to allow devices to use 5G signals to determine their location within one meter or less. This is considerably better than what is now possible with GNSS alone. Moreover, there will be a significant incentive for users and providers to implement such capability. As a terrestrial alternative to GPS, 5G is relevant across a wide range of threats, providing positioning and navigation superior to GNSS as long as base station synchronization remains adequate and timing synchronization can be passed to the 5G cells.
Our past experiences have taught us that India cannot solely depend on other countries to provide accurate PNT data. Learning from the Kargil War and the Russia-Ukraine war, policymakers need to consider all the possible PNT threats and not only the larger threats to make policy to develop/acquire a resilient PNT system from a plethora of available options. No PNT source, however, is foolproof; they all have their own strengths and weaknesses. Therefore, the best strategy is to use multiple, diverse PNT sources together that have different failure modes and characteristics so that the vulnerabilities of one source are counteracted by the strengths of another. Algorithms exist that can intelligently select and combine various PNT sources into a composite solution. To support Atmanirbhar Bharat, we require more startups offering effective solutions to a resilient PNT system. Taking preventive measures before facing an attack can sometimes be the best response. The best strategy to protect critical infrastructure is to use multiple, different PNT sources together. The earlier the detection, the quicker and more effective the recovery will be.
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